Comments on: Rolling contact bearings http://www.ret-monitor.com/articles/834/rolling-contact-bearings/ Specific mission-critical info for professionals Thu, 09 Feb 2012 17:07:39 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: terry http://www.ret-monitor.com/articles/834/rolling-contact-bearings/comment-page-1/#comment-5579 terry Wed, 29 Dec 2010 08:02:35 +0000 http://www.ret-monitor.com/articles/834/rolling-contact-bearings/#comment-5579 One point of interest that should be noted, is that rolling element bearings and journal bearings both operate under the same tribological principles. That is they both ideally have hydrodynamic contact conditions during operation. The journal bearing has a hydrodynamic oil film between the bearing shell and shaft journal supporting the load. The rolling element bearing has the same hydrodynamic oil film between the roller and race surfaces supporting the load. The friction losses in a journal bearing are due to viscous shearing of the hydrodynamic oil film. The friction losses in a rolling element bearing are mostly due to hysteresis, oil windage/churning, skidding, and lubricant hydraulic pumping losses. One point of interest that should be noted, is that rolling element bearings and journal bearings both operate under the same tribological principles. That is they both ideally have hydrodynamic contact conditions during operation.

The journal bearing has a hydrodynamic oil film between the bearing shell and shaft journal supporting the load. The rolling element bearing has the same hydrodynamic oil film between the roller and race surfaces supporting the load.

The friction losses in a journal bearing are due to viscous shearing of the hydrodynamic oil film. The friction losses in a rolling element bearing are mostly due to hysteresis, oil windage/churning, skidding, and lubricant hydraulic pumping losses.

]]>